According to Amazon’s review of Richard Hamblyn’s The Invention of Clouds, we only began thinking clouds could be categorized in 1802 when Luke Howard started giving public lectures. The very idea that clouds â€” the paradigm of uncatchable â€” could be divided into groups was (apparently) fascinating and thrilling. (Lamarck had also categorized clouds, but it didn’t catch on.)

A quick googly scan makes it seem that the cloud taxonomy is pretty messy. For example, the University of Illinois’ “cloud types” page lists four broad categories, and a list of miscellaneous clouds, each of which is categorized under one of the four basic types, evoking a “Huh?” reaction from at least one of us. The cloud taxonomy page at Univ. Missouri-Columbia lists eight types. Do you categorize by what they look like, how high they are, what they do (rain or not?), which celebrity profiles they resemble …? Categorizing clouds is truly a Borgesian task.

Placid mountains meander through the air, or tragic cordilleras cast a pall, overshadowing the day. They are what we call clouds. And their shapes are often strange and rare. Shakespeare observed one once. It seemed to be a dragon. That one cloud of an afternoon still kindles in his words and blazes down, so that we go on seeing it today. What are the clouds? An architecture of chance? Perhaps they are the necessary things from which God weaves his vast imaginings, threads of a web of infinite expanse. Maybe the cloud is emptiness returning, just like the man who watches it this morning.